INTRODUCTION 



A prominent department of activity throughout the history of the 

 Smithsonian Institution has been the scientific exploration of regions 

 imperfectly known, particularly in North America, although in recent 

 years this work has extended to all parts of the world. These investi- 

 gations have covered astronomy, anthropology, biology, geology, and 

 in fact all branches of science. Besides extending our knowledge 

 of nature and of man, there has been thus gathered and added to the 

 National Museum collections an enormous mass of material of very 

 great scientific interest and importance. 



During the year 191 7, the war greatly restricted the operations 

 in foreign lands and the field-work was therefore largely limited 

 to the United States. The accounts recorded herein have been 

 written chiefly by those who have carried on the work. 



Under the auspices of the Institution and in co-operation with the 

 U. S. Geological Survey and other departments of the Government, 

 there was carried on a few years ago a most thorough biological 

 and geological survey of the Panama Canal Zone. The results of 

 that important work are now being published in quite voluminous 

 form. Among these publications now in press are " Contributions to 

 the geology and paleontology of the Canal Zone, Panama, and geo- 

 logically related areas in Central America and the West Indies " pre- 

 pared under the direction of Thomas Way land Vaughn, to appear 

 as a National Museum Bulletin ; also a comprehensive monograph 

 on the " Mammals of Panama " by Edward A. Goldman. Numerous 

 other works having to do with Smithsonian Explorations during 

 recent years are enumerated in lists of publications issued by the 

 Institution at regular intervals each year. 



